<!doctype html>
<html>
  <head>
    <title>Notifications: Document for closing a notification in the "unload" event.</title>
  </head>
  <body>
    <script>
      var notification = new Notification('My Notification', {
          body: 'Created from a window.',
          icon: '/icon.png',
      });

      opener.postMessage('opened', '*');

      window.addEventListener('unload', function() {
          notification.close();

          opener.postMessage('closed', '*');
      });
    </script>
  </body>
</html>